A predominant performance-limiting factor in a wireless cellular communication system is interference. There are two interference sources including intra-cell interference and inter-cell interference.
Inter-cell interference arises because a transmitter (e.g., an eNB) in an adjacent cell schedules another User Equipment (UE) in the adjacent cell at the same frequency. If different cells do not operate in a Coordinated Multi-Point (CoMP) mode, then there will be a considerable influence of inter-cell interference upon a UE at the edge of a cell.
Intra-cell interference arises primarily from an interfering UE paired with a target UE in a Multi-User Multiple-Input Multiple-Output (MU-MIMO) mode. The MU-MIMO mode is an important transmission mode in the wireless communication system. In a cell, a transmitter can schedule a plurality of UEs to transmit over the same time and/or frequency resource as a pair of UEs. In a pair of UEs, different beam-forming is applied to the different UEs, and a multi-access mode is enabled at different spatial positions of the UEs. If a beam-forming matrix of one of the UEs is well orthogonal to a channel of the other UE, then intra-cell interference may be lowered. Furthermore the different UEs can be configured with different power in a power configuration scheme, or the different UEs can be configured with different spreading codes in a spreading code configuration scheme, where the UEs can suppress interference using a sophisticated receiver. The MU-MIMO technology in the existing system is implemented using the transmitter as a result of scheduling, where the transmitter schedules the paired UE dynamically for the target UE, and interference of the paired UE to the target UE may be intra-cell interference or inter-cell interference.
As the technology is advancing, there emerges the sophisticated receiver capable of suppressing interference as compared with a traditional receiver incapable of suppressing interference, and the target UE can suppress the interference of the paired UE using the sophisticated receiver to thereby improve the performance of the target UE in receiving a signal.
The MU-MIMO technology in the existing system is implemented at the network side (e.g., the eNB) as a result of scheduling, and if one of the MU-MIMO paired UE attempts to suppress interference of an interfering signal received by the UE, then a highly complicated operational flow may be necessitated.